Goss’s wilt and leaf blight is caused by the bacterium Clavibacter michiganensis subsp. nebraskensis (Cmn). The disease was first reported in Nebraska in 1969 and soon after in the surrounding states including Iowa. Corn breeders identified resistance to the bacterium and by the 1980s the disease was no longer a threat to corn production except in eastern Nebraska. In 2008, Goss’s leaf blight was reported in eight counties in Iowa. In 2011, the disease was widespread throughout the state and up to 50 percent yield losses occurred in some fields.

Calcium oxalate crystals in higher plants occur in five major forms namely raphides, styloids, prisms, druses and crystal sand. The form, shape and occurrence of calcium oxalate crystals in plants are species- and tissue-specific, hence the presence or absence of a particular type of crystal can be used as a taxonomic character. So far, four different types of needle-like raphide crystals have been reported in plants. The present work describes two new and unusual forms of raphide crystals from the tubers of Dioscorea polystachya—six-sided needles with pointed ends (Type V) and four-sided needles with beveled ends (Type VI). Both of these new types of needles are distinct from the other four types by each having a surrounding membrane that envelopes a bundle of 10–20 closely packed thin crystalline sheets. The previously known four types of needles have solid or homogenous crystalline material, surrounded by a membrane or lamellate sheath called a crystal chamber. Only the Type VI crystals have beveled ends and the needles of the other five types have pointed ends.

Dr. William August “Bill” Jensen, Ph.D., 87, passed away quietly on September 9, 2014 at the Sanctuary Facility in Dublin, Ohio after a long illness.

Bill led a very distinguished and full professional life. He received his Ph.B. (1948), M.S. (1950) and Ph.D. (1953) all from the University of Chicago. During his Ph.D. he held Atomic Energy and Public Health predoctoral fellowships at the University of Chicago and Carlsberg Laboratory in Copenhagen, Denmark.